DragAnObject_Start (changes)

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Programmer's DragAnObject Reference Manuals

» Part 15 – SWI Calls

» DragAnObject_StartDragAnObject

DragAnObject_Start

(SWI &49C40)

Use

The purpose of this call is to start dragging an object.

Notes

As per the DragASprite_Start, this SWI starts the dragging process (calling DragASprite_Start and in turn Wimp_DragBox on the clients behalf), usually in response to a Drag (Mouse_Click) Event.

The renderer can be a C (or assembler) function or a SWI (determined by setting bits 16 and 17 in the flags word).

void start_drag(...)
{
   _kernel_swi_regs regs, render;
  
   render.r[1] = (int) &icon;
  
   /* oh dear, bug in the wimp */
  
   render.r[4] =0;
   render.r[5] =0;
  
   regs.r[0] = some flags;
   regs.r[1] = Wimp_PlotIcon;
   regs.r[2] = (int) &render;
   regs.r[3] = (int) &bbox;
  
   _kernel_swi(DragAnObject_Start,&regs,&regs);
}

Example Code renderer

void _my_render(data)
{
   /* do the render */
  
}

void start_drag(...)
{
   _kernel_swi_regs regs;
   int render[4];
  
   /* render[0] ... render[3] will be passed to the function as parameters */
  
   render[0] = (int) data required by renderer;
  
   /* tell it we're a function and a module */
  
   regs.r[0] = some flags + (1<<16) + (1<<17);
   regs.r[1] = (int) _my_render;
   regs.r[2] = (int) &render;
   regs.r[3] = (int) &bbox;
  
   _kernel_swi(DragAnObject_Start,&regs,&regs);
}

See also

• DragAnObject Flags
• DragAnObject_Stop